1. Field of the Invention
The present invention relates generally to a leveling control system and method for heavy equipment, and more particularly to a leveling control system and method for heavy equipment in which a lower frame having a traveling means and an upper frame having working devices and a cab are coupled to each other through a tilting means, which can automatically or manually perform a leveling of the upper frame through the tilting means.
2. Description of the Prior Art
In heavy equipment, such as an excavator, a logging device, a crane, and the like, which is working on an inclined site, an upper frame is inclined to a horizontal surface depending on the ruggedness of ground.
When the heavy equipment is in an inclined state, inclination of an upper frame to a horizontal surface is changed as the upper frame is swiveled, and this causes the work to be done in an unstable state of the equipment. Also, as the center of gravity of the equipment is moved, a danger of overturning of the heavy equipment is increased.
In order to solve this problem, a method of moving the center of gravity of the heavy equipment near to ground through tilting of an upper frame on an inclined site has been used.
As a recent technology related to the above-described method, U.S. Pat. No. 6,609,581 discloses a tilt mechanism having an upper support being supported and tilted by two hydraulic cylinders.
Also, U.S. Pat. No. 6,158,539 discloses two hydraulic cylinders, upper bearing body support plate coupled to a center tilt shaft, and a lower plate.
As such tilting means is complicated, it is required that a user has a good experience in manually controlling the tilting through an expansion/contraction adjustment device of hydraulic cylinders with recognition of mutual relations among respective hydraulic cylinders, and thus it is not easy for a user to properly perform the tilting control.
Also, in the case where an operator manually controls the tilting of the heavy equipment as the equipment is moving in a rugged area, the operator should manipulate the leveling simultaneously with driving of the equipment. Accordingly, the operator cannot concentrate his attention on the driving of the equipment only, and thus the safety is lowered.
On the other hand, the leveling control of the heavy equipment is required not only when the equipment moves or performs a work on an inclined site but also when the equipment is loaded on a trailer. In this case, it is cumbersome for an operator to manually perform the leveling.
Accordingly, there is a need for development of a leveling control system and method that can properly perform a leveling control in diverse operation states of the heavy equipment.